JP4594521B2 - Axle force and moment transducer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring forces and moments applied to a wheel axle to analyze vehicle suspension and operating characteristics. In particular, the present invention relates to a motorcycle force transducer device used to control motorcycle testing based on dynamic force and moment measurements to improve motorcycle design or ride comfort and operability. However, it is not limited to this.
[0002]
[Prior art]
During the operation of a motorcycle or other motorcycle, various forces and moments are applied to the suspension system or chassis. Measuring these forces and moments is useful in designing and evaluating the performance of such vehicles. For example, in evaluating cornering, braking, and acceleration of motorcycles and other motorcycles, and evaluating stress and strain exerted on various positions of the chassis, axial forces F _X , F _Y , And F _Z, roll moment M _X and steering moment M _Z are useful.
[0003]
An “on-board” measuring device can be provided in the vehicle to measure the forces and moments that actually act. These devices can measure the forces and moments applied to the suspension system or chassis as the operator operates the vehicle in various terrain and situations, or can simulate other operating conditions in the laboratory. In such applications, measuring equipment is integrated with a suspension system or frame to measure and analyze the load applied to the vehicle suspension or chassis.
[0004]
Traditionally, the measuring device has been incorporated into a rotating wheel axle of a motorcycle or into a vehicle suspension. For example, in order to measure force, a strain gauge is incorporated in the inner bore of a wheel axle supported between suspension rods. By using a wheel axle with an inner bore, the strength of the wheel axle was reduced. Furthermore, incorporating measuring equipment into a rotating wheel axle requires the use of a slip ring or other device to perform the measurement, requiring complex transformations from the rotating wheel coordinate system to the fixed vehicle coordinate system. . When measuring equipment is incorporated into a suspension, the shape of the suspension results in large cross couplings and complex equipment.
[0005]
[Problems to be solved by the invention]
The present invention relates to a load transducer for measuring axial force and moment applied to a suspension load path of a motorcycle. The present invention can be adapted to perform “in-flight” data collection for “on-load” testing. The load transducer of the present invention includes first and second load cells connected to opposite ends of a central load axle that supports a rotating wheel hub.
[0006]
[Means for Solving the Problems]
In application, the central load axle and the first and second load cells are placed in a suspension load path between the rotating wheel, the load axle, and the suspension member of the suspension. A force is applied to the load axle and transmitted through the load cell to the suspension member. The load cell measures each load applied to the load axle in the suspension path in order to analyze the operation performance and operability of the motorcycle without using a device such as a slip ring or complicated conversion.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a side view of a motorcycle 10 including front and rear wheel assemblies 12, 14 with wheels supported by a rotating axle (not shown) coupled to a suspension member 16. During operation, various forces and moments are applied to the vehicle suspension and chassis through the wheels. In designing and evaluating performance, it is useful to measure and analyze the forces and moments applied to the vehicle suspension and chassis.
[0008]
FIG. 2 is a front view of one embodiment of a transducer assembly of the present invention that can be incorporated into a two-wheeler for testing and analysis. As shown, the transducer assembly includes a stationary rod or load axle 24 and a wheel hub 26 that supports the wheel 27 for rotation. The stationary rod 24 and the wheel hub 26 are rotatably connected via bearings 28 and 30 to form a wheel assembly. The stationary rod 24 is firmly connected to a vehicle frame (not shown) via fork rods or suspension members 32 and 33. During use of the vehicle, force is applied from the wheel 27 to the stationary rod or load axle 24 through the wheel hub 26. The transducer assembly of the present invention measures the force acting on the stationary rod 24 to analyze the actuation dynamics and stresses for various types of actuation, such as cornering and steering, so that the rod 24 is positioned at spaced positions. Two spaced apart triaxial load cells 34 and 36 are enclosed within individual connected housings.
[0009]
FIG. 2 shows the transducer assembly superimposed on a Cartesian xyz coordinate system. Two spaced triaxial load cells 34 and 36 are connected to a stationary rod or load axle 24 in a suspension load path to measure triaxial loads F _X , F _Y , and F _Z. Output measurements from load cells 34 and 36 are coupled to computer 38 for calculating F _X , F _Y , and F _Z for analysis. Furthermore, process data can be stored by the computer 38. As shown, the resulting force F _x applied to the frame Is obtained by F _X1 + F _X2 , and the resultant force F _Y is obtained by F _Y1 −F _Y2 , and the resultant force F _Z is obtained by F _Z1 + F _Z2 .
[0010]
The transducer assembly of the present invention is particularly suitable for motorcycles. The motorcycle rolls as shown in FIG. 3 with respect to the x-axis during cornering or other operations. FIG. 3 is a front view of the rolling of the transducer assembly about the x-axis. As shown in FIG. 3, triaxial load cells 34, 36 are used to measure forces and moments transmitted to the motorcycle suspension and chassis during cornering. The transducer assembly is relatively symmetrical about the center point 40 (the center of the stationary rod 24). The load cells 34, 36 measure the force at the wheel axle in the suspension load path from the point 40 on both sides of the point 40 via the stationary rod 24 in order to measure without complex coordinate transformation at the pivot point 40. Supported at an equal distance.
[0011]
A differential force F _z measured by the load cells 34 and 36 about the roll moment about the x-axis. Is multiplied by the distance R from the center point 40 to the load cells 34, 36. The distance R is the same for the load cells 34, 36 because the load cells 34, 36 are equally spaced from the center point 40. Thus, as shown, the load cell 34 measures F _Z1 and the load cell 36 measures F _Z2 and outputs it to the computer 38, as shown in FIG. 3-1, the wheel assembly roll moment or M _X. = (F _Z1 -F _Z2 ) × R is determined. If the load cell is not symmetric, the differential moment can be calculated based on multiplying the distance of the load cell 34 from the point 40 by F _{Z1 and} multiplying the distance of the load cell 36 from the point 40 by F _Z2 .
[0012]
FIG. 4 shows the rotation of the transducer assembly about the z axis for steering. The rotation around the z axis, that is, the steering movement, is measured based on F _X1 and F _X2 from the load cells 34 and 36. Since the load cell is symmetric about the z axis, the moment is calculated by the computer 38 as shown in FIG. 4-1, with M _Z = (F _X2 −F _X1 ) × R. Here, R is the distance from one of the load cells 34, 36 to the point 40.
[0013]
FIG. 5 is a flowchart showing the operation of the computer 38 for measuring the steering moment and the roll moment of F _X , F _Y , and F _Z and a vehicle such as a motorcycle. As shown block 46 and 48, to measure the F _X load by the load cell 34. Thereafter, as shown in block 50, the resulting force is calculated based on (F _X1 + F _Y1 ). Here, F _X1 is the force measured by the load cell 34, and F _X2 is the force measured by the load cell 36. The resulting force measurements are output or stored as shown in block 52.
[0014]
Similarly, as shown in blocks 54 and 56, forces F _Y1 and F _Y2 are measured by load cells 34 and 36 and the resulting F _y is obtained. The load is calculated based on (F _Y2 -F _Y1 ) as shown in block 58. Here, F _Y1 is the force F _Y from the load cell 34, and F _Y2 is the force F _Y from the load cell 36. Thereafter, the result at force F _Y is output or stored as shown in block 60. Similarly, the resulting force F _Z is calculated by F _Z = F _Z1 + F _Z1 as shown in blocks 62, 63, 64, 65 and 66, and output as shown in block 68, Or remember.
[0015]
The computer 38 also calculates roll moment and steering moment. Using the measured forces F _Z1 and F _Z2 from the load cells 34 and 36, the roll moment is calculated as shown in block 70. As explained above, the roll moment is equal to the difference between the forces F _Z1 and F _Z2 multiplied by the moment arm, which is the load cell distance R from point 40. The roll moment is output or stored as indicated at block 72. Similarly, the steering moment is calculated from the force components F _X1 and F _X1 measured by the load cells 34 and 36. The steering moment is calculated based on a value obtained by multiplying the difference between the value F _X2 measured by the load cell 36 and the value F _X1 measured by the load cell 34 by the distance R from the point 40 to the load cell. The steering moment is output or stored as indicated by block 76.
[0016]
FIG. 6 is a detailed view of one embodiment of a motorcycle front wheel assembly 80 incorporating the present invention. In this embodiment, the same parts as those of the wheel assembly shown in FIGS. 2 to 4 are designated by the same reference numerals. The stationary rod 24 is formed of an elongated member that extends along the longitudinal axis. Both ends of the elongated member extend laterally with respect to the longitudinal axis and are provided with screw holes 82. Bearings 28, 30 rotatably connect the wheel hub 26 to the outer periphery of the rod 24 between the ends of the rod 24 to rotatably support a wheel (not shown).
[0017]
The load cells 34 and 36 are supported at symmetrical positions spaced apart from the lateral ends of the stationary rod 24, and are disposed in a load path between the rod 24 and the fork rods or suspension members 32 and 33. ing. The load cells 34 and 36 are cylindrical three-axis load cells such as a load cell available from Michigan Scientific Co., Charlevoo, Michigan, and screw holes 84 and 86 (load bases) extending in opposite directions are first and first. A triaxial detection element is accommodated in housings provided on both housing surfaces. In the illustrated embodiment, the load cells 34 and 36 are disposed between the end of the stationary rod 24 and the suspension members 32 and 33. The load cells 34 and 36 are connected to both ends of the rod 24 via fasteners 88 having threads. The fasteners extend into cooperating threaded holes 84 in rod 24 and threaded holes 86 in load cells 34 and 36. The screw connection transmits the load from the rod 24 to the load cells 34 and 36 for measurement. Opposite surfaces of the load cells 34 and 36 are connected to fork rods or suspension members 32 and 33 through screw holes 86 of the load cells 34 and 36.
[0018]
An elongated fastener 90 extends through a fastener hole 91 provided in the suspension members 32, 33. The fastener 90 has a male threaded end 92 that is secured to a threaded hole 86 in the load cells 34 and 36 to connect the stationary rod 24 and load cells 34, 36 to the frame. The pinch bolt 94 fixes the fastener 90, and the fastener 90 is fixed to the suspension members 32 and 33.
[0019]
The elongated fastener 90 further includes a flange 98 that extends around the outer periphery of the fastener 90. The suspension members 32, 33 include side recesses 100. The load cells 32 and 36 extend into the recess 100 and the housings of the load cells 34 and 36 are aligned with the longitudinal surfaces 102 of the suspension members 32 and 33. The flange 98 provided on the fastener 90 is relatively thin, separating the housing surface of the load cells 34, 36 from the longitudinal surface 102, removing the suspension members 32, 33 from the axle 24, and transmitting the load through the load cells 34, 36. .
[0020]
The force paths for all forces F _X , F _Y and F _Z and the roll moment (M _X ) and steering moment (M _Z ) are exclusively from the wheel hub 26 to the bearings 28, 30, the stationary rod 24, the fastener 88. This is a path through to the load cells 34 and 36, and is measured by the load cells 34 and 36, and then passes through the fastener 90 to the motorcycle or vehicle suspension members 32 and 33. The surfaces of the load cells 34, 36 are spaced from the surface 102 in order to limit the influence of the suspension members 32, 33 (frame) to offset the moment or force acting on the stationary rod or load axle 24. As a result, the moment is limited to the load cells 34 and 36 for measurement and is transmitted to the suspension members 32 and 33 via the fastener 90. The faces of the load cells 34 and 36 are separated from the longitudinal surface 102 by spacer flanges 98 shown in detail in FIG.
[0021]
FIG. 8 shows one embodiment of a rear wheel assembly 110 incorporating the apparatus of the present invention in which two symmetrical triaxial load cells 34, 36 are mounted between rods 32-1 and 33-1. In this embodiment, the same reference numerals are used to indicate the components shown in FIGS. As shown in FIG. 8, the stationary rod 24-1 is formed of an elongated cylindrical member having a thread at the ends 112 and 114. Ends 112 and 114 are connected to female screw holes 86 of load cells 34 and 36 via spacer rings 116 having female and male screws. The spacer ring 116 provides firm support for the bearings 28, 30 and the wheel hub 24 to transmit moments to the load cells 34, 36 for taking measurements. The male screw provided on the ring 116 is screwed into the screw hole 86 of the load cell 34, 36 to fix the ring 116 to the load cell 34, 36, and the end portion of the stationary rod 24-1 with the thread is fixed to the female screw of the ring 116. Then, the rod 24-1 is fixed to the load cells 34, 36.
[0022]
As shown in FIG. 8, the housing surfaces of the load cells 34 and 36 are provided with a central protruding portion 118, that is, a load base. The central protruding portion 118 abuts against the rods 32-1 and 33-1 and restricts contact between the load cell surface and the rods 32-1 and 33-1. An end bolt 122 connects the load cells 34, 36 to the rods 32-1, 33-1 through the screw holes 84 at the central protruding portion 118. FIG. 9 is a detailed view of an elongate shaft with threads forming bolts 122, spacer rings 116, and stationary rods 24. Thus, the measured values of the two load cells 34 and 36 are transmitted to the computer 38, and F _X , F _Y , F _{Z, the} roll moment and the steering moment are measured as described above.
[0023]
Alternatively, the load cell may be located outside the suspension members or rods 32, 33 as in the embodiment shown in FIG. In this embodiment, parts similar to those shown in FIGS. 1 to 9 are given the same reference numerals. FIG. 10 is a front view of half of the transducer assembly for the sake of simplicity. As shown in FIG. 10, the stationary rod 24 includes an end 130 with a thread. The stationary rod 24 is smaller than the opening 132 provided in the suspension members 32 and 33 and extends into the female screw hole 136 of the load cells 34 and 36 through the opening. The stationary rod 24 is coupled to the load cells 34, 36 by cooperation of the threaded end 130 and the threaded holes 136 of the load cells 34, 36. The load cells 34 and 36 are bolted to the suspension members 32 and 33 by bolts 138 as shown in the figure. The opening 132 of the fork rods 32, 33 is larger than the size of the rod 24 and is sufficient to allow a force and moment path from the stationary rod 24 through the load cells 34, 36 to the suspension members 32, 33. A gap is provided between the stationary rod 24 and the suspension members 32, 33.
[0024]
In a variant, a load cell can be used to calculate the braking torque moment or the driving torque moment. Load cell of the present invention F _X, F _Y, and has been described with respect to three axes load cells 34, 36 to calculate the F _Z, to measure the braking torque, to calculate the moments in addition to F _X, F _Y, and F _Z Can also be used. The transducer assembly of the present invention can be incorporated into a two-wheeled vehicle as described above for performing an “on-road” test. Test data can be collected by an “on-board” computer for later analysis and use. In another aspect, the transducer assembly of the present invention can be incorporated into a laboratory simulation test application that applies simulation test loads and collects metrology data for analysis and use.
[0025]
Although a particular connection member is shown, it should be understood that various connection screws can be used to secure the load cell and shaft to the frame as described above. Although the invention has been described with respect to particular embodiments, it should be understood that the invention is not limited to the particular embodiments shown and can be used with any vehicle including a two-wheeled vehicle such as a bicycle.
[0026]
While the invention has been described in terms of a preferred embodiment, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
[Brief description of the drawings]
FIG. 1 is a perspective view of a motorcycle to which the present invention can be adapted to measure actuation forces and moments.
FIG. 2 is a front view of one embodiment of a transducer assembly of the present invention.
FIG. 3 is a front view during cornering or rolling, and FIG. 3A is a diagram illustrating calculation of a roll moment.
FIG. 4 is a plan view during steering, and FIG. 4A is a diagram illustrating calculation of a steering moment.
FIG. 5 is a flowchart of the operation of one embodiment of a computer coupled to a transducer assembly for calculating operating characteristics.
FIG. 6 is a detailed view of one embodiment of the transducer assembly of the present invention.
FIG. 7 is a detailed view of a fastener that couples a suspension member to a load cell for measuring operating characteristics.
FIG. 8 is a view of a variation of a transducer assembly for measuring operating characteristics.
FIG. 9 is an exploded view showing the components of the transducer assembly of FIG. 9;
FIG. 10 is a partial view of one side of one embodiment of the transducer assembly of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Motorcycle 12, 14 Wheel assembly 16 Suspension member 24 Stationary rod 26 Wheel hub 28, 30 Bearing 32, 33 Suspension member 34, 36 Triaxial load cell

Claims (20)

In the assembly,
A load axle having spaced apart first and second ends, and an elongated portion positioned between the first and second ends;
A wheel hub rotatably connected to the load axle around an outer periphery of the load axle;
First and second load cells having sensing elements configured to measure force;
The first load cell is coupled to the first end of the load axle, and the load axle can be coupled to the first suspension member through the first load cell during use;
The assembly, wherein the second load cell is coupled to the second end of the load axle, and the load axle can be coupled to a second suspension member through the second load cell during use. The assembly of claim 1, wherein
The assembly, wherein the first and second load cells are triaxial load cells. The assembly of claim 1, wherein
The first and second load cells have a first surface and a second surface spaced from the first surface;
The first end of the load axle is coupled to the first surface of the first load cell;
The second end of the load axle is connected to the first surface of the second load cell;
In order to connect the first suspension member to the load axle through the first load cell, the first suspension member is connected to the second surface of the first load cell;
An assembly, wherein the second suspension member is connected to the second surface of the second load cell to connect the second suspension member to the load axle through the second load cell. The assembly of claim 1, wherein
A first fastener for connecting the first suspension member to a hub of the first load cell;
A second fastener for connecting the second suspension member to the hub of the second load cell;
Furthermore, to transmit a load through the first and second load cells,
A first flange adjacent to the hub of the first load cell that separates the first suspension member from the first load cell;
An assembly comprising: a second flange adjacent to the hub of the second load cell that separates the second suspension member from the second load cell. The assembly of claim 4, wherein
The first fastener includes the first flange, and the second fastener includes the second flange. The assembly of claim 1, wherein
The first and second load cells have a first surface and a second surface spaced from the first surface;
The first end of the load axle extends through a hole in the first suspension member and is coupled to the first surface of the first load cell;
The first suspension member is coupled to the first surface of the first load cell at a position radially spaced from the hole of the first suspension member;
The second end of the load axle extends through a hole in the second suspension member and connects to the first surface of the second load cell;
The assembly, wherein the second suspension member is connected to the first surface of the second load cell at a position radially spaced from the hole of the second suspension member.   The assembly according to claim 1 incorporated in a motorcycle. In the assembly,
A load axle having spaced apart first and second ends, and an elongated portion positioned between the first and second ends;
First and second load cells having sensing elements configured to measure force, wherein the first end of the load axle is coupled to the first load cell, and the second end of the load axle A portion connected to the second load cell;
Also, the assembly is
A first suspension member connected to the first end of the load axle through a first intermediate connection to the first load cell;
And a second suspension member connected to the second end of the load axle through a second intermediate connection to the second load cell. 9. The assembly of claim 8,
The first and second load cells have a first surface and a second surface spaced from the first surface;
The first end of the load axle is coupled to the first surface of the first load cell;
The second end of the load axle is connected to the first surface of the second load cell;
The assembly for forming the first and second intermediate connections to the first and second load cells;
A first fastener for connecting the first suspension member to the second surface of the first load cell;
An assembly comprising: a second fastener for connecting the second suspension member to the second surface of the second load cell. The assembly of claim 9, wherein
To transmit a load through the first and second load cells,
The first fastener includes a first flange that separates the first suspension member from the first load cell;
The second fastener includes an second flange that separates the second suspension member from the second load cell. 9. The assembly of claim 8,
The first and second load cells have a first surface and a second surface spaced from the first surface;
The first end of the load axle is coupled to the first surface of the first load cell;
The second end of the load axle is connected to the first surface of the second load cell;
The assembly is
At least one first fastener connecting the first surface of the first load cell to the first suspension member;
An assembly comprising: at least one second fastener connecting the first surface of the second load cell to the second suspension member. The assembly of claim 11, wherein
The first suspension member includes a first hole,
The second suspension member includes a second hole,
The first end of the load axle extends through the first hole and connects to the first load cell;
The assembly, wherein the second end of the load axle extends through the second hole and couples to the second load cell. 9. The assembly of claim 8,
The first and second load cells are:
A force Fx, a force Fy and a force Fz with respect to Cartesian coordinate axes x, y and z are configured to be measured, and using the measured force Fx, force Fy and force Fz from the first and second load cells, force An assembly comprising a processor connected to the first and second load cells for calculating Fx, force Fy and force Fz . 9. The assembly of claim 8,
A processor operatively connected to the first and second load cells;
The first and second load cells measure axial forces along the z-axis relative to the load axle with respect to Cartesian coordinate axes x, y and z ;
Wherein the processor, the roll moment M _X against the load axle, calculated by the formula _{M X = (F Z 1 -F} Z 2) R, in this formula, F _Z2 is, z-axis first load cell is measured F _Z1 represents the axial force along the z-axis measured by the second load cell, and R represents the distance between the first and second load cells. 9. The assembly of claim 8,
A processor operatively connected to the first and second load cells;
The first and second load cells measure axial forces along the x-axis relative to the load axle with respect to Cartesian coordinate axes x, y and z ;
Wherein the processor, the steering moment M _Z against the load axle, calculated by the formula _{M Z = (F X1 -F X2} ) R, in this formula, F _X1 is along the x-axis where the first load cell is measured The assembly indicates an axial force, F _X2 indicates an axial force along the x-axis measured by the second load cell, and R indicates a distance between the first and second load cells. A method for testing,
A first suspension member is connected to the load axle through a first intermediate connection to a first load cell connected to a first end of the load axle and to a second load cell connected to a second end of the load axle. Connecting the second suspension member to the load axle through the second intermediate connection of
Applying a test load to the load axle;
Receiving output measurements from the first and second load cells;
Calculating based on output measurements of the first and second load cells. The method of claim 16, wherein
The method wherein the load axle is incorporated into a motorcycle and the test load is applied by an “on-road” test simulation. The method of claim 16, wherein
The test load is applied in a laboratory simulation. The method of claim 16, wherein
Calculating a roll moment M _X about the Cartesian coordinate axes x, y, and z by using an expression of M _X = (F _Z2 −F _Z1 ) R using output measurement values from the first and second load cells,
In this equation, F _Z2 indicates the axial force along the z-axis measured by the first load cell, F _Z1 indicates the axial force along the z-axis measured by the second load cell, and R is the first and second A method of indicating the distance between load cells. The method of claim 16, wherein
Calculating a steering moment M _Z with respect to the Cartesian coordinate axes x, y, and z by using an expression of M _Z = (F _X1 -F _X2 ) R using output measurement values from the first and second load cells,
In this equation, F _X1 represents the axial force along the x-axis measured by the first load cell, F _X2 represents the axial force along the x-axis measured by the second load cell, and R is the first and second A method of indicating the distance between load cells.

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